Project 2: New Gene Expression in Cell Culture Models of Ischemia In Project 2, primary neurons cell culture models will be used to investigate the neurocidal or neuroprotective effects of gene products whose expression is altered by cerebral ischemia, as identified in Project 1. The long-term objective is to identify endogenous mechanisms of neuronal death and neuroprotection that can be exploited in the treatment of stroke. These hypothesis are: (A) some of the same gene products whose expression is altered by cerebral ischemia in vivo are affected similarly in cell culture models; (B) these models can be used to determine which gene products influence whether ischemic neurons survive or die; (C) the ability of altered gene expression to modify neuronal injury in cell culture can predict effects of altered expression in vivo. The specific aims are to: (1) determine which candidate neurocidal and neuroprotective gene products show altered expression in cell culture models of neuronal ischemia and cell death; (2) investigate which gene products exhibiting increased expression have neurocidal or neuroprotective functional effects, using antisense oligodeoxynucleotides (ODNs) to block their expression; and (3) investigate which gene products exhibiting decreased expression have functional effects, using viral vectors to enhance their expression. Northern and Western analysis will be used to detect expression of candidate genes and gene products, and Alamar blue fluorescence and lactate dehydrogenase will be used to quantify neurotoxicity. A spectrum of cell culture models-hypoxia with glucose deprivation in cortical neuron cultures, excitatory amino acid exposure in cortical neuron cultures, and K+/- withdrawal-induced apoptosis in cerebellar granule cell cultures-will be employed. Phosphorothioate antisense ODNs will be used to inhibit translation of, and single- and double-mutant replication-defective HSV vectors will be used to overexpress, candidate gene products. The most promising of these will be tested in vivo, using antisense and gene transfer techniques, in Project 3.